1 /* $OpenBSD: vis.c,v 1.26 2022/05/04 18:57:50 deraadt Exp $ */
2 /*-
3 * Copyright (c) 1989, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <sys/types.h>
32 #include <errno.h>
33 #include <ctype.h>
34 #include <limits.h>
35 #include <string.h>
36 #include <stdlib.h>
37 #include <vis.h>
38
39 static int
isoctal(int c)40 isoctal(int c)
41 {
42 u_char uc = c;
43
44 return uc >= '0' && uc <= '7';
45 }
46
47 static int
isvisible(int c,int flag)48 isvisible(int c, int flag)
49 {
50 int vis_sp = flag & VIS_SP;
51 int vis_tab = flag & VIS_TAB;
52 int vis_nl = flag & VIS_NL;
53 int vis_safe = flag & VIS_SAFE;
54 int vis_glob = flag & VIS_GLOB;
55 int vis_all = flag & VIS_ALL;
56 u_char uc = c;
57
58 if (c == '\\' || !vis_all) {
59 if ((u_int)c <= UCHAR_MAX && isascii(uc) &&
60 ((c != '*' && c != '?' && c != '[' && c != '#') || !vis_glob) &&
61 isgraph(uc))
62 return 1;
63 if (!vis_sp && c == ' ')
64 return 1;
65 if (!vis_tab && c == '\t')
66 return 1;
67 if (!vis_nl && c == '\n')
68 return 1;
69 if (vis_safe && (c == '\b' || c == '\007' || c == '\r' || isgraph(uc)))
70 return 1;
71 }
72 return 0;
73 }
74
75 /*
76 * vis - visually encode characters
77 */
78 char *
vis(char * dst,int c,int flag,int nextc)79 vis(char *dst, int c, int flag, int nextc)
80 {
81 int vis_dq = flag & VIS_DQ;
82 int vis_noslash = flag & VIS_NOSLASH;
83 int vis_cstyle = flag & VIS_CSTYLE;
84 int vis_octal = flag & VIS_OCTAL;
85 int vis_glob = flag & VIS_GLOB;
86
87 if (isvisible(c, flag)) {
88 if ((c == '"' && vis_dq) ||
89 (c == '\\' && !vis_noslash))
90 *dst++ = '\\';
91 *dst++ = c;
92 *dst = '\0';
93 return (dst);
94 }
95
96 if (vis_cstyle) {
97 switch (c) {
98 case '\n':
99 *dst++ = '\\';
100 *dst++ = 'n';
101 goto done;
102 case '\r':
103 *dst++ = '\\';
104 *dst++ = 'r';
105 goto done;
106 case '\b':
107 *dst++ = '\\';
108 *dst++ = 'b';
109 goto done;
110 case '\a':
111 *dst++ = '\\';
112 *dst++ = 'a';
113 goto done;
114 case '\v':
115 *dst++ = '\\';
116 *dst++ = 'v';
117 goto done;
118 case '\t':
119 *dst++ = '\\';
120 *dst++ = 't';
121 goto done;
122 case '\f':
123 *dst++ = '\\';
124 *dst++ = 'f';
125 goto done;
126 case ' ':
127 *dst++ = '\\';
128 *dst++ = 's';
129 goto done;
130 case '\0':
131 *dst++ = '\\';
132 *dst++ = '0';
133 if (isoctal(nextc)) {
134 *dst++ = '0';
135 *dst++ = '0';
136 }
137 goto done;
138 }
139 }
140 if (((c & 0177) == ' ') || vis_octal ||
141 (vis_glob && (c == '*' || c == '?' || c == '[' || c == '#'))) {
142 *dst++ = '\\';
143 *dst++ = ((u_char)c >> 6 & 07) + '0';
144 *dst++ = ((u_char)c >> 3 & 07) + '0';
145 *dst++ = ((u_char)c & 07) + '0';
146 goto done;
147 }
148 if (!vis_noslash)
149 *dst++ = '\\';
150 if (c & 0200) {
151 c &= 0177;
152 *dst++ = 'M';
153 }
154 if (iscntrl((u_char)c)) {
155 *dst++ = '^';
156 if (c == 0177)
157 *dst++ = '?';
158 else
159 *dst++ = c + '@';
160 } else {
161 *dst++ = '-';
162 *dst++ = c;
163 }
164 done:
165 *dst = '\0';
166 return (dst);
167 }
168 DEF_WEAK(vis);
169
170 /*
171 * strvis, strnvis, strvisx - visually encode characters from src into dst
172 *
173 * Dst must be 4 times the size of src to account for possible
174 * expansion. The length of dst, not including the trailing NULL,
175 * is returned.
176 *
177 * Strnvis will write no more than siz-1 bytes (and will NULL terminate).
178 * The number of bytes needed to fully encode the string is returned.
179 *
180 * Strvisx encodes exactly len bytes from src into dst.
181 * This is useful for encoding a block of data.
182 */
183 int
strvis(char * dst,const char * src,int flag)184 strvis(char *dst, const char *src, int flag)
185 {
186 char c;
187 char *start;
188
189 for (start = dst; (c = *src);)
190 dst = vis(dst, c, flag, *++src);
191 *dst = '\0';
192 return (dst - start);
193 }
194 DEF_WEAK(strvis);
195
196 int
strnvis(char * dst,const char * src,size_t siz,int flag)197 strnvis(char *dst, const char *src, size_t siz, int flag)
198 {
199 int vis_dq = flag & VIS_DQ;
200 int vis_noslash = flag & VIS_NOSLASH;
201 char *start, *end;
202 char tbuf[5];
203 int c, i;
204
205 i = 0;
206 for (start = dst, end = start + siz - 1; (c = *src) && dst < end; ) {
207 if (isvisible(c, flag)) {
208 if ((c == '"' && vis_dq) ||
209 (c == '\\' && !vis_noslash)) {
210 /* need space for the extra '\\' */
211 if (dst + 1 >= end) {
212 i = 2;
213 break;
214 }
215 *dst++ = '\\';
216 }
217 i = 1;
218 *dst++ = c;
219 src++;
220 } else {
221 i = vis(tbuf, c, flag, *++src) - tbuf;
222 if (dst + i <= end) {
223 memcpy(dst, tbuf, i);
224 dst += i;
225 } else {
226 src--;
227 break;
228 }
229 }
230 }
231 if (siz > 0)
232 *dst = '\0';
233 if (dst + i > end) {
234 /* adjust return value for truncation */
235 while ((c = *src))
236 dst += vis(tbuf, c, flag, *++src) - tbuf;
237 }
238 return (dst - start);
239 }
240
241 int
stravis(char ** outp,const char * src,int flag)242 stravis(char **outp, const char *src, int flag)
243 {
244 char *buf;
245 int len, serrno;
246
247 buf = reallocarray(NULL, 4, strlen(src) + 1);
248 if (buf == NULL)
249 return -1;
250 len = strvis(buf, src, flag);
251 serrno = errno;
252 *outp = realloc(buf, len + 1);
253 if (*outp == NULL) {
254 *outp = buf;
255 errno = serrno;
256 }
257 return (len);
258 }
259
260 int
strvisx(char * dst,const char * src,size_t len,int flag)261 strvisx(char *dst, const char *src, size_t len, int flag)
262 {
263 char c;
264 char *start;
265
266 for (start = dst; len > 1; len--) {
267 c = *src;
268 dst = vis(dst, c, flag, *++src);
269 }
270 if (len)
271 dst = vis(dst, *src, flag, '\0');
272 *dst = '\0';
273 return (dst - start);
274 }
275